This invention relates to the filling of needle-less injectors, and, in particular embodiments, to devices and methods for filling or refilling modular gas-pressured needle-less injectors.
Traditionally, fluids such as medications are injected into patients, either subdermally or intradermally, using hypodermic syringe needles. The body of the syringe is filled with the injectable fluid and, once the needle has pierced the patient""s skin, the syringe plunger is depressed so as to expel the injectable fluid out of an opening in the needle. The person performing the injection is often a trained medical services provider, who manually inserts the hypodermic needle between the layers of a patient""s skin for an intradermal injection, or beneath the skin layers for a subcutaneous injection. However, injections are also routinely performed by laypersons, as in the case of diabetics self-administering insulin injections.
Needle injectors suffer from increased danger of contamination exposure to health care workers administering injections, and to the general public when such injectors are not properly disposed of In fact, safety considerations surrounding needle injectors are of such paramount concern that they are prohibited from some locations. This may severely hamper the ability of those in need of regular injections to receive convenient and timely medical attention. One heavily burdened population is diabetic children who require insulin injections, since children are not permitted to bring needle injectors to some school campuses. Various hospitals are similarly working to minimize the use of needles; some going so far as to design and mandate a completely needle-free environment.
Jet injectors are generally configured to avoid some or all of these problems inherent in needle-containing injectors. Typically, needle-less medication injectors use either an expansion spring or a compressed inert gas to propel the fluid medication (via a push rod plunger) through a small orifice (an injector nozzle) which rests perpendicular to and against the injection site. The fluid medication is generally accelerated at a high rate to a speed of between about 800 feet per second (fps) and 1,200 fps (approximately 244 and 366 meters per second, respectively). This causes the fluid to pierce through the skin surface without the use of a needle, resulting in the medication being deposited in a flower pattern under the skin surface.
U.S. Pat. No. 6,447,475, U.S. Pat. No. 6,080,130, U.S. Pat. No. 6,063,053, U.S. Pat. No. 5,851,198, U.S. Pat. No. 5,730,723, and U.S. patent application Ser. No. 09/834,476, now U.S. Pat. No. 6,613,010, each of which is incorporated by reference in its entirety, describe needle-less injectors incorporating a gas power source, thus obviating some of the limitations inherent in compression spring injectors and addressing many of the concerns of conventional jet injectors. The injectors described therein have a pre-filled and self-contained compressed gas for providing pressure to inject medication into the skin surface of a patient without the use of a needle.
Some injectors may be furnished to a hospital or consumer in a pre-filled state (i.e., the needle-less injector already contains a volume of the fluid sought to be injected). Filling such a device a substantial amount of time prior to use presents a variety of concerns, not the least of which is the risk of bacterial contamination on the exterior of such a device owing to fluid remaining on the exterior thereof after the filling operation is completed.
Additionally, as some ailments require periodic injection of varying amounts of a medication, it may be impractical for a user to employ a pre-filled needle-less injector. By design, a pre-filled injector already contains a particular amount of a medication, and in the case of an injection whose requisite volume cannot be determined in advance, one can not assume that the volume of a pre-filled injector will be suitable. Also, if multiple injections are to be administered throughout the day, one may not wish to carry several pre-filled injectors, as this may be cumbersome and inconvenient.
Finally, various medications or other products suited for use in conjunction with a needle-less injector are provided in either a solid or binary form. Solid medications may be lyophilized, for example, wherein a component of the final injectate is in a freeze-dried or similar form. The lyophilized component may be mixed with a liquid shortly before injecting the resulting solution by needle-less injection. Binary medications may include, for example, two liquids that are mixed together shortly before injection of the resulting mixture. U.S. Pat. No. 6,223,786, U.S. Pat. No. 6,302,160, and U.S. patent application Ser. No. 10/034,561 describe various methods and devices for performing this type of mixing and also filling needle-less injectors with such a mixture, and each is incorporated by reference in its entirety.
It is therefore an object of an embodiment of the instant invention to provide an apparatus and method that obviates, for practical purposes, the above-mentioned limitations.
In one embodiment of the instant invention, a coupling device is provided. The coupling device may connect the dispensing end of a needle-less injector to a vessel containing a fluid. In various embodiments, the vessel may be a Luer syringe, filling equipment configured to fill a needle-less injector, or another appropriate apparatus. The coupling device may be contoured such that, when it is mated to a needle-less injector and fluid is transferred therethrough, the fluid does not contact the exterior surface of the dispensing end of the needle-less injector. The coupling device may also include a fitting for removably affixing the device to a needle-less injector at one end, and may further include an attachment mechanism for removably affixing the device to an appropriate vessel at the opposing end. In preferred embodiments, graduations on either the vessel, the injector, or both provide a user with visual cues regarding filling, so that the user can determine when a desirable volume of fluid has been filled into the injector.
In another embodiment of the instant invention, a filling device is provided. The filling device may mate to the dispensing end of a needle-less injector, and may include a coupling device and a vessel. In various embodiments, the vessel may be a Luer syringe or other apparatus configured to fill a needle-less injector. The coupling device may be contoured such that, when the filling device is mated to a needle-less injector and fluid is transferred therefrom, the fluid does not contact the exterior surface of the dispensing end of the needle-less injector. The filling device may also include a fitting for removably affixing the device to a needle-less injector at one end, and may further include an attachment mechanism for affixing the coupling device to the vessel. In preferred embodiments, graduations on either the vessel, the injector, or both provide a user with visual cues regarding filling, so that the user can determine when a desirable volume of fluid has been filled into the injector.
In still another embodiment of the instant invention, a method is provided for filling a needle-less injector. The method may include providing a coupling device configured to be simultaneously mated to a needle-less injector and attached to a vessel, and to provide fluid communication therebetween. An appropriate vessel and needle-less injector may be mated to the coupling device, and fluid may then be expelled from the vessel, through the coupling device, and into the needle-less injector. Graduations may be included on the vessel, the injector, or both; graduations allowing a user to ascertain the volume of fluid that has been transferred. Filling may be terminated upon reaching a predetermined volume, as indicated by observing the graduations (i.e., in those embodiments wherein graduations are included). The direction of flow may be reversed after expelling a desired volume of fluid from the vessel to remove gas bubbles from the injector. Finally, the vessel, the coupling device, and the injector may be disconnected from one another.
In yet another embodiment of the instant invention, a storage vial adapted for use with a coupling device is provided. The storage vial may be contoured, such that, when it is mated to a coupling device, a fluid transferred between the storage vial and the coupling device does not contact the exterior surface of the storage vial. The storage vial may contain a product that is in solid or liquid form. A product in liquid form, such as a fluid, may be drawn from the storage vial through the coupling device and into a vessel configured on the opposite end of the coupling device. Alternatively, a fluid may be introduced into the storage vial, wherein it may mix with a liquid or solid (e.g., lyophilized) product already contained therein. The resulting mixture may then be drawn from the storage vial through the coupling device and into a vessel configured on the opposite end of the coupling device. The vessel may then be used in accordance with the methods described above with respect to alternative embodiments of the present invention to fill a needle-less injector.